Add support for PageUp & PageDown

Wox/MainWindow.xaml.cs

@@ -315,6 +315,18 @@ namespace Wox
                     e.Handled = true;
                     break;
 
+                case Key.PageDown:
+                    resultCtrl.SelectNextPage();
+                    toolTip.IsOpen = false;
+                    e.Handled = true;
+                    break;
+
+                case Key.PageUp:
+                    resultCtrl.SelectPrevPage();
+                    toolTip.IsOpen = false;
+                    e.Handled = true;
+                    break;
+
                 case Key.Enter:
                     AcceptSelect(resultCtrl.AcceptSelect());
                     e.Handled = true;

Wox/ResultPanel.xaml.cs

@@ -162,5 +162,27 @@ namespace Wox
                 OnOnMouseClickItem(item.DataContext as Result);
             }
         }
+
+        public void SelectNextPage()
+        {
+            int index = lbResults.SelectedIndex;
+            index += 5;
+            if (index >= lbResults.Items.Count)
+            {
+                index = lbResults.Items.Count - 1;
+            }
+            Select(index);
+        }
+
+        public void SelectPrevPage()
+        {
+            int index = lbResults.SelectedIndex;
+            index -= 5;
+            if (index < 0)
+            {
+                index = 0;
+            }
+            Select(index);
+        }
     }
 }